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Insp Repts 50-259/88-06,50-260/88-06 & 50-296/88-06 on 880314-21.Violation Noted.Major Areas Inspected:Ultrasonic Exam of Unit 2 Reactor Vessel Shroud Access & Inservice Insp Status for Unit 2 & 3
	ML20151V285
Person / Time
Site:	Browns Ferry
Issue date:	04/12/1988
From:	Blake J, Coley J; NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:	;
Shared Package
ML20151V276	List: ML20151V273; ML20151V279; ML20151V285;
References
	50-259-88-06, 50-259-88-6, 50-260-88-06, 50-260-88-6, 50-296-88-06, 50-296-88-6, IEIN-88-003, IEIN-88-3, NUDOCS 8805030005
	Download: ML20151V285 (8)
	v • d • e

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DO 880 U951TED STATES

0q'o h!UCLEAR REGULATORY COMMISSIOM ~

REGION 11

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101 MARIETTA GTREET, N.W.

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I *j ATLANTA, GEORGI A 3o323 t

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Report Nos.: 50-259/88-06, 50-260/88-06, and 50-296/88-06

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Licensee: Tennessee Valley Authority

6N 38A Lookout Place -

1101 Market Street

Chattanooga, TN 37402-2801

Docket Nos.: 50-259, 50-260 and 50-296 License Nos.: DPR-33, DPR-52,

and DPR-68

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Facility Name: Browns Ferry 1, 2, and 3

., Inspection Conducted: March 14-21, 1988

Inspector: [, M bkt77 41_ A% f!f(I

Date Signed

J. L. Coley J f ,

Approved by: M N. b

J. J. Blake, Chief (/

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Date Signed !

Materials and Processes Section

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Division of Reactor Safety l

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SUMMARY

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Scope: This routine, announced inspection was in the areas of ultrasonic

1 examination of Unit 2 reactor vessel shroud access cover as referenced in NRC

Information Notice No. 88-03 and General Electric (GE) Surveillance Instruction j

Letter (SIL) No. 462 and inservice inspection status for Units 1 and 3. !

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Results: One violation was identified - Failure to Follow Procedure for !

Prevention of Foreign Material in Reactor Vessel Cavity.

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8805030005 880420 ' ,

PDR ADOCK 05000259! '

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REPORT DETAILS

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1. Persons Contacted

Licensee Employees ,

D. Brown, Nondestructive Examination Engineer

1 *T. Gilbert, Nondestructive Examination Unit Supervisor

e *E. Hartwig, Project Manager

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C. Madden, Regulatory Compliance t

J. Martin, Assistant to Plant Manager

J. Robert, Fuel Inspection Project Manager i

J. Whitaker, Nondestructive Examination Engineer

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Other licensee employees contacted included construction craftsmen, l

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engineers, technicians, operators, mechanics, security force members, and i

office personnel. .

Other Organization i

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General Electric i

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J. Steininger, Site Manager !

J. Self, Manager Inspection Services i

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NRC Resident Inspectors l

G. Paulk, Senior Resident Inspector !

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E. Christnot, Resident Inspector, Resident Inspector j

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Attended exit interview

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2. Exit Interview !

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The inspection scope and findings were summarized on March 21, 1988, with )

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those persons indicated in paragraph 1 above. The inspector described l

the areas inspected and discussed in detail the inspection findings. No ;

, dissenting comments were received from the licensee. The following new 1

item was identified during this inspection:

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i Violation 50-260/88-06-01, Failure to Follow Procedure for Prevention of

Foreign Material in Reactor Vessel Cavity, paragraph 5.c.

The licensee did not identify as proprietary any of the materials provided

to or reviewed by the inspector during this inspection.

3. Licensee Action on Previous En'orcement Matters

) This subject was not addressed in the inspection.

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4. Unresolved Items

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Unresolved items were not identified during this inspection.

5. Ultrasonic Examination of Unit 2 Reactor Vessel Shroud Access Cover

a. Background Information ,

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Jet pump BWRs are designed with access holes in the shroud support

plate which is located at the bottom of the annulus between the core i

shroud and the reactor vessel wall. Each reactor vessel has two such

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holes which are located 180 degrees apart. These holes are used for ,

access during construction and are subsequently closed by welding a i

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plate over the hole. The covers and shroud support ledge are Inconel

Alloy 600 material. The connecting weld material is also Inconel 600

(Alloy 182 or 82).

1 The high residual stresses resulting from welding, along with a ;

i possible crevice geometry of the weld, when combined with less than '

ideal water quality, present a condition conducive to integranular

stress corrosion cracking (ISGCC). This has been recognized by

a General Electric and, as a result, they have developed a remotely .

operated ultrasonic testing capability for detecting cracks in the

cover plate welds. The first use of this custom ultrasonic testing t

fixture was at Peach Bottom Unit 3. !

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On January 21, 1988, intermittent short cracks were found in the weld

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heat-affected zone around the entire circumference of the covers at ;

1 Peach Bottom Unit 3. It is estimated that cracking exists ever 50% ;

to 60% of the circumference with cusps as deep as 70% through the i'

. wall. It is believed that cover plate welds have not been inspected

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previously on any other BWR. It is possible that the cracking is ;

generic and may, therefore, affect all BWRs with jet pumps.

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General Electric has identified three concerns if failure of the f

access hole cover plates is postulated due to weld cracking:

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(1) Loose parts - In the event of complete failure of the access !

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cover weld during normal reactor operation, the slightly higher

bottom head arca pressure would lift the cover out its recess.

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3 It would most likely fall to one side, but there is a potential i

for it to be swept into the recirculation pump suction line I

causing severe pump damage. j

(2) Core flow bypass (normal operation) - Loss of one or both cover

1 plates would allow some recirculation system flow to bypass the

core, from the jet pump discharge through the open access hole

to the recirculation pump suction. This flow transient would be

readily detectable and would require reactor shutdown.

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(3) Core flow bypass (Loss of Coolant Accident) - If the access hole

cover plate welds were to fail as a direct consequence of a

recirculation suction line break, the bypass path would prevent

the emergency core cooling system from reflooding the core. to

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the 2/3 level . The core spray system would be capable of- ,

maintaining adequate core cooling provided there has been no t

degradation in the core spray piping. <

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In reply to the generic concern of IGSCC in the shroud access cover [

addressed in NRC Information Notice No. 88-03 and GE SIL No. 462, TVA. ;

scheduled GE to perform the ultrasonic (UT) examination of Browns !

i Ferry Unit 2 access covers during the week of March 14-18, 1988. j

GE has performed the shroud access cover examinations for several i

utilities since their identification of cracks at Peach Bottom and no '

additional cracks have been identified. TVA's Browns Ferry Unit 2,

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however, is the first vessel to be inspected that has the same access l

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cover configuration and thickness as Peach Bottom. In addition,

like Peach Bottom, the access covers at Browns Ferry do not have a j

centering hole for the GE test fixture. This makes centering the ;

fixture on the access cover a critical operation. The GE automated l

j ultrasonic SMART system bases all measurements on the assumption that :

the fixture is centered. The examiner's evaluation as to whether an [

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indication is actually a crack or perhaps a crevice area will depend l

{ on critical measurements based on the fixture being centered. There- i

fore, the inspector had made prior arrangements with TVA to be !

notified when these e/aminations would be performed in order that NRC

I could be assured that the UT examinations and evaluation of data was i

as accurate as technically possible. [

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i b. Review of Procedures and Certification / Qualification Record (73052) !

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The inspector reviewed GE's examiner certification and qualification !

records to ensure that personnel used for data acquisition, analysis

and sizing of IGSCC had been qualified in accordance with the ,

Electric Power Research Institute (EPRI)/ Boiling Water Reactors !

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Owners Group (BWROG)/NRC training agreement. The examination

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procedure was reviewed to determine if the procedure adequately

described the method of examination, extent of inspection coverage j

and techniques necessary to ensure defect detection in Inconel plate i

and weld metal materials. Two TVA procedures were also reviewed as a

j result of foreign material being discovered and recovered from the

! reactor vessel cavity during the pre-examination work activities,

i Procedures reviewed and the inspector's comments regarding these

' procedures are listed below:

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Procedure No. Title

GE-UT-57R1 Remote Ultrasonic Examination Procedure

for Detection of _IGSCC in Shroud

Support Access Cover Plate

TVA - Standard Prevention of Foreign Material in the

Practice BF-7.8 Reactor Vessel Cavity and Torus ;

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TVA - Standard Lost or Unsecured Article Recovery

Practice BF-7.7

The inspector's review of UT-57 R1 revealed that this procedure was

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technically adequate. However, paragraphs 6.5.1 and 7.5 incorrectly

stated that: "all reflectors which exceed 15 percent full screen

height (FSH) above the average noise level shall be recorded on the

floppy disk." The GE SMART System ectually only records the first

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signal inside the gate that exceeds 15% FSH above the average noise

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level (similar to a strip recorder) on the floppy disk. Therefore, .

the procedure statement could mislead the licensee as to exactly

how much data they are saving. Some systems (TVA's Intraspect-98

included) will record on the floppy disk all signals inside the gate

above a threshold amplitude. Clarification of the procedure state- ,

ment was discussed with TVA and GE's Level III Examiners. Both

agreed that a note should be added to the procedure to clarify the

. SMART System's recording capabilities. Addendum 1 to the procedure t

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was subsequently approved and issued incorporating this clarifica- I

tion. The inspector's review of TVA's Standard Practice 7.7 and 7.8 l

} revealed both procedures to be administratively and technically i

adequate documents. !

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During the above reviews, the inspector also noted that GE's "in

vessel" IGSCC procedure, which uses immersion testing technique, has :

not been demonstrated at EPRI and GE does not have EPRI qualified [

examiners for sizing IGSCC using an automated system. GE has !

qualified the SMART automated system for IGSCC examination but not '

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for immersion testing. GE also has qualified IGSCC sizing examiners

but they are only qualified to use the manual method. However, TVA '

is not required, but has elee*:., to perform the IGSCC examinations

of the access cover as stated in NRC information Notice 88-03. The 1

1 qualification of procedure and personnel for immersion testing and I

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automated system sizing has not been addressed in the EPRI/BWROG/NRC

training agreement because the access cover examinations are outside

the initial work scope of the agreement. The examinations are

basically a "best effort attempt" to obtain information concerning

the soundness of the access covers and the GE examiners have demon-

strated at EPRI their ability to identify, evaluate and size IGSCC.

The inspector recognizes that differences in examination techniques

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may add some additional percentage of error to the examinations

results. However, significant and appreciative information can

be obtained using the procedure and personnel as qualified. The

inspector discussed this training oversight with GE's manager of

inspection service and was informed that GE is presently considering

setting up an in vessel defect detection and sizing demonstration at

a GE facility in the near future and that NRC would be notified. The

inspector also intended to witness the system's calibration, scanner

positioning, examination and sizing methods for accuracy.

Certification / qualification records were reviewed for the following

GE examiners:

Examiners Data Acquisition Analysis Sizing

B.L.N. / /

W.C. / / /

S.W. / /

R.W.A /

In addition to the review of procedures and examiner certification /

qualification records, the inspector also requested the following

information for review:

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Fabrication weld records to determine if the weld root was

welded with 82 or 182 inconel

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Construction radiographs, if available, to determine the

position and orientation of any crevice

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Drawing of the access cover

Only the access cover drawings were provided to.the inspector during

the inspection,

c. Observation of Work Activities (73753)

GE was scheduled to start the ultrasonic examination of the shroud

access covers on March 15, 1988. However, delays were experienced in

shipping of the necessary ultrasonic test equipment to site. When

the equiement arrived GE discovered that the motor to the transducer

manipulator was broken. In addition to other equipment problems

encounted by GE, delays occurred because TVA's site NDE personnel

were not aware that their contract with GE required TVA to perform

all in-vessel camera and fixture positioning work. The site NDE

examiners were not experienced with working in-vessel and work

proceeded in a cumbersome manner. On March 17, 1988, at approxi-

mately 4:00 p.m., the ultrasonic scanner was removed from the vessel

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annulus region at zero degrees azimuth in order to trouble shoot a

problem with the translator (radial position) of the UT head. The i

underwater TVA camera had been left pointing at.the access cover when l

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the scanner was removed. It was 'later noticed, on the TV monitor,

i that a small screw or bolt-like object was resting on top of the !

j- access cover.

Prior to the foreign object being seen, part of .the troubleshooting !

involved installing screws in pre-existing holes on the front-right

and back-left of the scanner. The screws were added in an attempt to

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stabilize the front end plate movement that resulted in the problem ,

with the translator. Once the foreign object was seen on the -

monitor, all work on the scanner was stopped. On March 18, 1988, GE

I sent for in-vessel workers and equipment technicians from San Jose,

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California to retrieve the objects observed in-vessel and to fix the

i equipment problems that vore. delaying the examinations.

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By 6:00 p.m. Saturday, March 19, 1988, the objects haa been removed '

i' from the vessel and the UT scanner inspected and tentatively found to. *

be satisfactory. The articles found in the vessel were thought to be' e

i parts of a rivet since loose rivets were found on the refueling floor '

i inside the control zone. The UT scanner was lowered back in the

vessel annulus and positioned on the access hatch cover.

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4 examination started at approximately 7:00 p.m. and had proceeded "

i several inches, when the UT examiner observed on the TV monitor, that

the transducer was not indexing with the SMART System Display. The

apparent cause was mechanical slippage in the worm gear on the UT

fixture. The ultrasonic scanner was again removed from the vessel

annulus to investigate the problem. The inspector observed the

disassembly of the scanner and noted a number of holes in the

, apparatus that did not have screws. In addition, a roll pin was ;

missing from the shaft. The inspector inquired as to whether there I

l had been a roll pin in the scanner prior to the examinations. GE's '

equipment technician responded that, a roll pin was not required

because the shaft was pressed into the housing but no one could J

answer the inspector's question. However, GE later determined that '

j one of the objects in the vessel was the roll pin and the other .

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object was a head of a rivet off the scanner. The inspector inquired

also as to who had the accountability records on the scanner and

which of the holes that were missing screws were recorded as missing ;

4 a screw in that area. Neither GE nor TVA personnel could answer the ;

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question even though the scanner was -supposed to have been examined

thoroughly as a result of the recovery plan within the previous 24 i

i hours and loose or missing parts identified. The inspector also !

inquired as to why the screws installed in the scanner were not tight j

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and why lanyards or some fatisafe method of attaching the screws to I

the mechanizism had not been used. The inspector was informed that i

the scanner cover screws were not tightened because when they were

j tight they would bind the mechanizism and prevent its operation. The

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inspector noted that all TVA equipment such as lights, etc in the

control zone that were going in or had been in the vessel did have

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lanyards or locking devices. Accountability records on the in-vessel

lights had sketches showing each screw or missing screw. The

inspoctor concluded from his review of TVA equipment and records that

the only equipment that had been in-vessel and not adequately

documented or protected from loose parts becoming detached was the UT

equipment GE was using. GE, however, was working to TVA's Quality

Assurance Program.

The inspector, informed the licensee that loose parts inside the

control area (rivets on refueling floor), inadequate accountability

of missing or attached parts on the scanner, failure to insure loose

screws were attached with a lanyard or some form of locking devise,

and failure of GE or TVA to properly inspect the scanner for loose or

missing parts prior to putting this mechanism back into the reactor

vessel after tne first event, is a violation of TVA Standard Practice

BF-7.8. This violation was reported to the licensee as item no.

50-260/88-06-1, Failure to Follow Procedure for Prevention of Foreign

Material in P.eactor Vessel Cavity.

As a result of the continuous equipment problems encountered with

their examination of the shroud access cover during the week of

March 14-20, 1988, GE requested and permission was granted from the

licensee for the examination effort be halted until GE could complete

development of an updated ultrasonic system for these examinations.

This work is presently in process in San Jose, California and should

be available within the next thirty days.

Within the areas examined, no violations or deviations were identified

except as noted in paragraph 5.c above.

6. Inservice and Inspection Status - Units 1 and 3

The inspector held discussions with the NDE Unit supervisor concerning

inservice inspection activities on Units 1 and 3. The inspector was

informed that most of TVA's efforts are focused on Unit 2 at the present

time. However, some visual and surface examination work was being

performed on Unit 3. The supervisor stated that the next large job for

the NDE unit would be the replacement of the 12 inch riser piping

safe-ends.

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ML20151V285

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